Not sure how old, I estimate midlate 1970s.
Original battery, NiCD 7000. 7.2 volts. 1.3mAh
My replacement Part number: CC7000 NIMH 7.2 volts. 2.1 mAh
https://en.wikipedia.org/wiki/Nickel%...
Makita company.
1951 ... more like 1915
https://en.wikipedia.org/wiki/Makita